More turns increase stray capacitance, which shunts high-frequency common-mode currents. For 2m (144 MHz), 5 turns on a Mix 61 core works better than 14 turns.
When common-mode currents flow on the outside of your coax, three problems emerge: Building And Using Baluns And Ununs Pdf
| Type | Impedance Ratio | Typical Core (FT-240) | Wire Turns | |------|----------------|----------------------|-------------| | 1:1 Current Balun | 50:50 | FT-240-43 | 14 bifilar | | 4:1 Unun | 200:50 | FT-240-61 | 2:1 ratio | | 49:1 Unun | 2450:50 | FT-240-43 (stacked) | 7:1 ratio | More turns increase stray capacitance
Many popular antennas—such as dipoles, Yagis, and loop antennas—are "balanced." They have two identical legs that are symmetrical to ground. Building And Using Baluns And Ununs Pdf